ABB Surge Arrestors in Ludvika have for a long time had a problem to keep the moisture at a steady state in the production of their ZnO-powder, that is used to produce varistors.Some black-box models of the spray drying process have been designed and evaluated to find a solution for the problem. After evaluating the collected data it has been found that variations in the supply voltage causes control difficulties for the operator. A cascade control system was designed, consisting of three PI control loops designed with lambda tuning. The disturbance in the supply voltagewas used as a feed forward in the control system.At the end of the project the control system was installed, and tests were made to verify the functionality of the regulator. It was shown that most of the variations in the moisture of the powder could be eliminated using small resources, through purchase of a process controller and four power meters.

In industrial control systems PID-control remains the prevalent strategy, also for processes that would benefit from model based control. The purpose of this thesis is to evaluate whether model based control can be readily implemented in an industrial control system. To this end a simulated surge tank with a simulated industrial control system is studied. For evaluation two scenarios with specified objectives are selected.Following a review of LQR and versions of MPC, Predictive Functional Control (PFC) is considered the most suitable for implementation. PFC is a form of MPC developed with industrial applications in mind and therefore has several advantages for implementation in an industrial control system.

The purpose of this essay is to examine which factors that influence the design of internal control in municipal context and how well it works. We choose seven municipals, where we interviewed the administrative managers, the chairmen of the committees and two persons of the staff in each activity unit. The interviews were performed by telephone, due to the keeping of the essay?s timeframe.The theory in our essay comprises eight hypotheses. These hypotheses were operationalised into different variables aiming to make statistical tests possible.

The purpose of this research is to examine the implications of the provisions in the Swedish Code of Corporate Governance (the Code) concerning auditor attestation of the internal control report. We will focus on how the auditors? augmented responsibilities will affect the efficiency in the audit process.Our research indicates that the main benefit from reviewing the internal control report is achieving more reliable internal controls, which results in greater prevention of misstatements in the financial statements. This will affect the efficiency in the audit process since the auditor can place more reliance on internal controls when performing audit procedures. This implies that the benefits of preventing misstatements could outweigh the efforts and resources spent on reviewing the internal control report..

This master thesis reviews advances in detection and diagnosis of static friction (stiction) in control valves. Control valves suffering from stiction results in oscillating control loops which in turn decreases both the process stability and reliability. Perstorp AB sees a necessity to automatically detect stiction in valves before the effects of the malfunctioning valves have become too severe. This thesis presents an introduction to maintenance, control loops and how stiction in valves can affect performance of control loops.A selection of methods presented in the literature are introduced and examined using normal operating data from the site in Perstorp. Common for all selected methods is their intuitive ideas and that they are based on normal operating data and minimum amount of process knowledge.

Abstract Title: A messy story ? a case study of Secorocs process flow of DTH-pipes Presentation date: 2010-06-02 Course: Bachelor thesis in businessAuthor: Kristoffer ForsmanAdvisor: Kjell GustafssonKeywords: Management control, process control, lean production, process flow analysisPurpose: The purpose of this bachelor thesis is to develop an overview of the process flow for a specific product, and with the help of this mapping based on a lean production philosophy show possible improvement proposals and how these can lead to a more efficient process flow.Methodology: I have used a case study of Secorocs DTH-pipes and my primary data are gathered through interviews and observations. I have used theoretical framework to establish a process flow analysis. This is to obtain data on process activities and whether they are creating value or not. This leads to a current mapping of the situation in Secoroc on DTH-pipes and then analyzed and suggestions for improvement are developed.Conclusions: That by using the above mentioned mapping of process flow of DTH-pipes, problem areas could be illustrated.

???This study has been made with the purpose of gaining an understanding of how a Swedish company may think and act concerning their internal control. An American body, COSO, have for some time published documents containing guidelines for how companies should go about this process, however, when conducting this study we were not aware of the extent to which companies in Europe and mainly Sweden used them. In order to learn about this, and also to gain an understanding of when these guidelines are appropriate, we conducted a case study with a large-sized, multinational Swedish company. We also conducted an interview with an expert in internal control monitoring, Anna-Clara af Ekenstam of Pricewaterhouse Coopers, in order to get the perspective of the evaluators in this process and to gain some insight as to whether our case is typical in Sweden or not. We found that our company disregards certain aspects of internal control condoned by COSO, while performing better on other dimensions.

There has been an increasing interest for ranking of Swedish health care and a lot of emphasis has been placed on the creation of indicators in order to rank hospital units. However, essays on to what extent the choice of statistical method affects the final result of the ranking of health care units have not been given the same attention. For this particular reason, the main objective of this essay has been to investigate whether the choice of statistical model has a significant impact or not on the final result, by using five different, more or less common, statistical approaches: bar charts (with and without confidence intervals), control charts, logistic regression, multi-level analysis using shrunken residuals. The analyzed material in the essay comprises 24119 patients that all have been prescribed some form of the lipid-reducing medicine statin. According to directives given by Region Skåne, doctors are encouraged to prescribe a particular type of statin medicine, namely Simvastatin, which has been proved to be equally effective, but significantly cheaper than other statin medicines.

In this thesis, a computer program that in a simple way can calculate the performance of control loops at the refinery Preemraff Lysekil has been created. The computer program has been adapted to the environment at Preemraff Lysekil. Theories for evaluation has been studied in aspect of reliability and of automatic implementation. The evaluation has been carried out from data collected directly from control loops at the refinery and from simulated control loops with implemented errors. Among the studied methods are Harris index and Stattin´s oscillation index.

The aim of this Master?s thesis is to examine the function of the budget as a means of control within an organisation in the public sector. To accomplish this, a case study has been conducted on a certain business unit within Luftfartsverket responsible for providing Air Traffic Control services. The thesis is built on a framework of contemporary theories of budgeting and includes a brief discussion of the weaknesses usually associated with the traditional budget. The conclusion of the study is that the use of budget as a means of financial control within Luftfartsverket is not efficient enough at the moment.

Title: Co-operative, prevent or complement? - An essay on the relationships between control systems. Authors: Kim Eriksson and Victoria KarlssonPurpose: The essay aims to describe the relations between control systems and how they related to each other, based on an operationalization of the control systems. Research question: What are the control systems relations to each other? With regards whether control systems co-operative, prevents and/or complement each other.Theoretical framework: The essays theoretical framework is based on Malmi and Browns (2008) description of five different control systems and control mechanisms associated with each control system.   Research methodology: The method was based on three different data collection methods. These methods were observations, documentation, and semi-structured interviews.Conclusions: It is concluded that the control systems has comprehensive relations. Control systems have more, than one, relation to each other..

The secondary control must be part of the production plan, since the capacity will bedeployed in advance, just as the primary control. The activation of the new frequencycontrol should be preformed in Vattenfall's operations centers (DC) to minimizecommunication delay. Vattenfall needs to work towards a more holistic optimizationsystem. The main issue for Vattenfall Generation is not how we produce but ratherwhen, which is done with creation of bids. This is where there is the mostopportunity for improvement.

Core strength is important in order to be able to do all types of daily activities. One way to exercise ones core muscles is according to the pre- choreographed program Fokus. Previous studies have shown that core training gives better balance and stability in the core and also improved techniques, body awareness and control. Aim: To evaluate the core endurance strength, the balance and the studied individuals self estimated body awareness and control after six weeks of training according the pre- choreographed program Fokus. Methods: A total of 14 people volunteered to participate in the study, six of which completed the study.

Core strength is important in order to be able to do all types of daily activities. One way to exercise ones core muscles is according to the pre- choreographed program Fokus. Previous studies have shown that core training gives better balance and stability in the core and also improved techniques, body awareness and control. Aim: To evaluate the core endurance strength, the balance and the studied individuals self estimated body awareness and control after six weeks of training according the pre- choreographed program Fokus. Methods: A total of 14 people volunteered to participate in the study, six of which completed the study.

Studier har visat att det finns ett samband mellan syskonplacering och locus of control, medan andra studier inte funnit något samband. Syftet med denna studie är att undersöka relationen mellan syskonplacering, kön och locus of control ur ett hälsoperspektiv hos gymnasieelever i årskurs 3. I undersökningen deltog 147 gymnasielever ifrån fem skolor i Kronobergs län. Resultatet visade att kön och syskonplacering samvarierade med intern health locus of control (F= 3,01;p< 0,03; ES= 6,2) och att syskonplacering och kön tillsammans inte visade någon signifikant inverkan på extern health locus of control (F= 2,20;p=<0,09; ES= 4,6). Fyndet kan indikera att manliga mellanbarn i större utsträckning strävar efter en intern health locus of control än kvinnliga mellanbarn.Nyckelord: Syskonplacering, health locus of control, intern- och extern locus of control, kön..